FP27-6 Progression of vertebral fractures despite long-term biochemical control of acromegaly: a prospective follow-up study

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: FP27-Pituitary: Acromegaly and Prolactinoma
Clinical
Sunday, June 16, 2013: 10:45 AM-11:15 AM
Presentation Start Time: 11:10 AM
Room 135 (Moscone Center)

Poster Board SUN-92
Kim M.J.A. Claessen*1, Alberto M. Pereira2, Natasha M. Appelman-Dijkstra1, Neveen Agnes Therese Hamdy1, Herman Kroon3, Margreet Kloppenburg4 and Nienke R Biermasz1
1Leiden University Medical Center, Netherlands, 2Leiden University Medical Center, The Netherlands, 3Leiden University Medical Center, Leiden, The Netherlands, 4Leiden University Medical Center
Background

GH and IGF-1 are important regulators of bone growth during the life span. In active acromegaly, pathologically high levels increase bone turnover and bone mineral density (BMD), which is sustained after long-term disease control. Recently, we reported an impressively high prevalence (59%) of vertebral fractures (VFs) in long-term controlled patients, despite normal mean BMD. It remains to be elucidated whether these fractures occur during the active phase of acromegaly or during follow-up in remission. Another clinically relevant question is how to identify acromegaly patients at risk for (vertebral) fractures, since BMD appears to be a poor predictor of fracture risk in this form of secondary osteoporosis. We designed a prospective follow-up study over 2.5yr to study progression of VF in controlled acromegaly.

 

Methods

Fifty-eight patients (mean age 61.8±10.9yr, 41% female) with controlled acromegaly for 17.6±7.2yr were included. A standardized questionnaire on medical history was completed. On conventional spine radiographs, vertebrae Th4-L4 were assessed for VFs according to the Genant method. VF progression was defined as the development of incident fractures and/or minimal 1-point increase in Genant scoring in already existing deformities. Potential risk factors for progression were assessed.

Baseline BMD was assessed by DXA. In a subset of patients (N=20), DXA was repeated after 2.5yr to assess BMD changes over time. World Health Organization (WHO) criteria were used to define osteopenia (T-score between -1.0 and -2.5) and osteoporosis (T-score ≤-2.5). In a subset of patients (N=9), bisphosphonate-treatment was initiated; these data were presented separately.

 

Results

Patients without bisphosphonates (N=49, baseline T-score ≤-2.5 in N=2) had baseline VF prevalence of 63%, and a mean number of 2.3±1.4 VF. Baseline VF prevalence was highest in males, and unrelated to BMD. We found progression of VFs in 20% of patients, especially in males and in case of ≥2 VFs at baseline. No other risk factors for VF progression were identified. VF progression was not related to BMD values or the change in BMD over time, at either the lumbar spine or total hip.

Patients using bisphoshonates (N=9, baseline T-score ≤-2.5 in N=3) had a baseline VF prevalence of 78%, with a mean VF number of 3.3±2.4. In this subgroup, VF progression was observed in 7 out of 9 patients (78%), despite bisphosphonate-treatment.

Conclusion

Acromegaly patients have a high prevalence of VFs, also those in long-term biochemical control. This first longitudinal study shows that 20% of acromegaly patients have progressive VFs, especially those with ≥2 VFs at baseline. In a small subset of patients using bisphosphonates, we report a progression rate of 78%. Further research should address the question whether acromegalic patients require treatment for these fractures and whether they will benefit from bisphosphonates.

Nothing to Disclose: KMJAC, AMP, NMA, NATH, HK, MK, NRB

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

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